BP, the company that owned the Louisiana oil rig that exploded last week, spent years battling federal regulators over how many layers of safeguards would be needed to prevent a deepwater well from this type of accident.

One area of immediate concern, industry experts said, was the lack of a remote system that would have allowed workers to clamp shut Deepwater Horizon's wellhead so it would not continue to gush oil. The rig is now spilling 210,000 gallons of oil a day into the Gulf of Mexico.

In a letter sent last year to the Department of the Interior, BP objected to what it called "extensive, prescriptive regulations" proposed in new rules to toughen safety standards. "We believe industry's current safety and environmental statistics demonstrate that the voluntary programs…continue to be very successful."

That was one in a series of clashes between the industry and federal regulators that began during the Clinton administration. In 2000, the federal agency that oversaw oil rig safety issued a safety alert that called added layers of backup "an essential component of a deepwater drilling system." The agency said operators were expected to have multiple layers of protection to prevent a spill.

But according to aides to Sen. Bill Nelson, a Florida Democrat who has followed offshore drilling issues for years, the industry aggressively lobbied against an additional layer of protection known as an "acoustic system," saying it was too costly. In a March 2003 report, the agency reversed course, and said that layer of protection was no longer needed.

"There was a big debate under the Bush administration whether or not to require additional oil drilling safeguards but [federal regulators] decided not to require any additional mandatory safeguards, believing the industry would be motivated to do it themselves," Carl Pope, Chairman of the Sierra Club told ABC News.

A second area of focus emerging Friday involved the cement casing that was supposed to seal the well and prevent gaps from opening between the outside of the well pipe and the inside of the hole drilled into the sea floor. If cement is not poured properly, oil and natural gas can escape – a cause of more than a dozen previous well blowouts in the Gulf.

House Energy and Commerce Chairman Henry Waxman Friday sent a letter to Halliburton, the company responsible for pouring the cement seal, asking company executives to brief committee investigators on conditions at the rig, and preserve all documents relating to their work on the sea floor.

Elmer Danenberger, an expert on offshore drilling who retired from the U.S. Department of the Interior in January, told ABC News he is worried that "lack of attention" during the pouring of the cement could be to blame.

"With these cementing operations it's just a matter of not being attentive enough," he said. "What you want is a closed system. You want the cemented pipe totally sealing the well bore. If you don't have that, you have problems."

Because the well us under more than a mile of water, it may be some time before investigators have more clarity on what exactly went wrong. But Brent Coon, a lawyer who sued BP over a previous deadly oil facility explosion, said he has obtained a restraining order to prevent the company from doing anything to cover up the cause of the accident.